Walmarts often stock foods that are hard to get elsewhere. We have
found sushi supplies for example, as well as brand name peanut butters etc.
Another reason is the USDA Beef. Yes you will pay more for it, but it is tender
and a big taste of home.
Sam's Club
Locations,
Costco Locations

RV?

Walmart is a good place to start if you need camping gear something that
will help fix, repair or otherwise install in your RV. Unlike Walmarts at home
though, there is not a "sleep-over"
policy.